Abstract: A laser system for producing a laser beam, the laser system having top and bottom heat-sinking bars forming the structure of the laser system and plurality of disks comprising a laser material mounted on both the bottom heat-sinking bar and the top heat-sinking bar. Also mounted on both heat-sinking bars is a plurality of pump diode bars. Each pump diode bar is preferably mounted opposite a corresponding laser disk on the opposite heat-sinking bar. The pump diode bars and the disks are symmetrically mounted on the top and bottom heat-sinking bars, so that each heat-sinking bar has an alternating pattern of pump diode bars and laser disks. The laser system is configured such that the lasing beams impinge on the disks with an incidence angle far off normal.

Abstract: A laser apparatus, comprising a layer fabricated of a lasing medium, the layer having a top surface and a bottom surface, and a first substrate layer fabricated of a laser-inactive material, the first substrate being diffusion-bonded to the layer of lasing medium, wherein the lasing medium comprises a crystalline, polycrystalline or glass material doped with ions. The lasing medium selected for fabrication of the laser apparatus of this invention comprises neodymium-doped yttrium vanadate material and laser-inactive material of the substrate comprises an yttrium-aluminate or yttrium vanadate material. The layers of material are oriented so that the thermal expansion coefficients along the crystallographic axes of the materials match or nearly match.

Abstract: A solid state pump cavity comprising a laser rod encased by diffusion bonding inside an outer cladding. The outer cladding provides the ability to efficiently conduct heat away from the laser rod. The outer cladding is also configured to absorb spontaneous laser radiation that would otherwise be re-amplified by the laser rod. Diffusion bonding of the outer cladding to the laser rod forms a seamless optical boundary between the outer cladding and the laser rod. An alternative embodiment of the pump cavity comprises multiple segments of laser rod and outer cladding assemblies coupled together with undoped sections that are diffusion bonded to the ends of the laser rod and outer cladding assemblies.

Abstract: A high gain optical amplifier and method. Generally, the inventive amplifier includes a first crystal having an axis and a first index of refraction and a second crystal bonded to the first crystal about the axis and having a second index of refraction. The first index is higher than the second index such that light through the first crystal is totally internally reflected. In the illustrative embodiment, the first crystal is Yb:YAG with an index of approximately 1.82, the second crystal is Sapphire with an index of approximately 1.78, and the axis is the propagation axis. The invention is, in its preferred embodiment, a light guide fabricated out of crystalline materials, diffusion bonded together. If the core of the light guide is doped with laser ions, high gain amplifiers made be designed and operable over a large étendue.

Abstract: A solid state waveguided structure a core fabricated of a lasing medium, diffusion-bonded to a cladding fabricated of a laser-inactive material. The medium of the core comprises a lutetium-aluminum-garnet material doped with ions of ytterbium, lutetium-aluminum-garnet material doped with ions of neodymium, and lutetium-aluminum-garnet material doped with ions of thulium, and the laser-inactive material of the cladding comprises an yttrium-aluminum-garnet material. A method of fabricating a solid state waveguided structure with improved characteristics comprising using a combination of a trivalent ions of ytterbium-doped lutetium-aluminum-garnet core and a yttrium-aluminum-garnet cladding.

Abstract: A high gain optical amplifier and method. Generally, the inventive amplifier includes a first crystal having an axis and a first index of refraction and a second crystal bonded to the first crystal about the axis and having a second index of refraction. The first index is higher than the second index such that light through the first crystal is totally internally reflected. In the illustrative embodiment, the first crystal is Yb: YAG with an index of approximately 1.82, the second crystal is Sapphire with an index of approximately 1.78, and the axis is the propagation axis. The invention is, in its preferred embodiment, a light guide fabricated out of crystalline materials, diffusion bonded together. If the core of the light guide is doped with laser ions, high gain amplifiers made be designed and operable over a large étendue.

Abstract: A laser comprising a master oscillator and a loop phase conjugate mirror (Loop-PCM) for substantially eliminating transient relaxation oscillations to instead form controlled sustained pulsations. In a preferred embodiment suitable for material processing applications with high power requirements, the master oscillator is part of a Phase Conjugate Master Oscillator Power Amplifier (PC-MOPA). A method for processing a material using a Loop-PCM by determining and using an optimal pulse fluence, duration and spacing is provided. Using pulses of the kind which are produced by the transient, and normally not desirable, relaxation oscillations common to Nd:YAG and other lasers, relaxation oscillations with controllable pulse duration, repetition rate and duty cycle are generated, making it ideal for materials processing.

Abstract: A multi-pass, integrating diode pump cavity for an Er,Yb:glass laser is provided. The diode pump cavity comprises two end members of undoped glass sandwiching a center section of glass of the same composition as that of the two end members but doped with erbium and ytterbium ions. The two end members are each provided with a curved outer surface, which is coated with a reflective coating. At least one of the curved surfaces includes a slit through the reflective coating for transmission of pump laser light from a pump diode laser bar into the cavity. The diode pump cavity is small, compact, efficient, and eye-safe.

Abstract: A laser pump cavity apparatus with integral concentrator provides improved thermal lensing control, cooling and fracture strength. The concentrator is formed around a doped solid-state laser medium by diffusion bonding, using a material different than the doped laser medium and with a substantially lower index of refraction, higher thermal conductivity and higher stress fracture strength than the doped laser crystal. The concentrator has a top cladding layer with a cylindrical focusing surface and a bottom cladding layer with a cylindrical focusing surface and may have edge cladding layers. Cold plates, each of which also has one cylindrical surface, are placed in thermal contact with the cylindrical surfaces of the top and bottom cladding layers. The cylindrical surfaces preferably have hyperbolic or quasi-hyperbolic shape. The laser pump cavity apparatus is preferably pumped with several laser diode arrays in directions transverse to a laser beam axis.

Abstract: A compact diode pumped laser including a nonuniform, single-or double-sided diode pumped laser head and a polarization output coupled (POC) resonator. The POC resonator employs reflections from two opposing uncrossed roof prism mirrors to produce a uniform near field and far field beam with diffraction or near diffraction limited quality. The single laser head particularly includes a laser rod, a sapphire envelope located about the rod, an area of antireflection coating located on the sapphire envelope between the rod and the diode array, and a high reflectivity nickel-plated indium layer located on the sapphire envelope on the surface thereof outside of the area of antireflection coating.

Abstract: A compact diode pumped laser including a nonuniform, single- or double-sided diode pumped laser head and a polarization output coupled (POC) resonator. The POC resonator employs reflections from two opposing uncrossed roof prism mirrors to produce a uniform near field and far field beam with diffraction or near diffraction limited quality. The single laser head particularly includes a laser rod, a sapphire envelope located about the rod, an area of antireflection coating located on the sapphire envelope between the rod and the diode array, and a high reflectivity nickel-plated indium layer located on the sapphire envelope on the surface thereof outside of the area of antireflection coating.

Abstract: A glass fiber laser system includes a laser resonator cavity having a resonant path and an erbium-doped glass fiber lasing element with an output of from about 1.5 to about 1.6 micrometers within the laser resonator cavity. A light source directed into an input end of the glass fiber lasing element optically pumps the lasing element to emit light. A passive Q-switch lies along the resonant path within the laser resonator cavity. The Q-switch is formed of a host material having a concentration of uranium ions therein, so as to be a saturable absorber of the light emitted by the lasing element. The Q-switch is preferably a uranium-doped fluoride crystal such as U:CaF.sub.2, U:SrF.sub.2, or U:BaF.sub.2.

Abstract: A laser pump cavity assembly having a laser rod with a ground outer surface positioned concentrically within an annular jet sleeve which is, in turn, positioned concentrically within an annular outer sleeve. The outer sleeve is coated with a dielectric coating having slits therein arranged to receive focused optical pump radiation from respective laser diode arrays, the pump radiation being transmitted through the outer sleeve and jet sleeve to excite the laser rod. The jet sleeve is positioned to define cooling fluid chambers between the outer sleeve and the jet sleeve, and between the jet sleeve and the laser rod, and is provided with a series of jet holes for directing cooling fluid to impinge perpendicularly on the laser rod. The end faces of the jet sleeve and outer sleeve are further coated with dielectric material to enhance the efficiency of the device. The cooperating end caps which mount the outer sleeve, jet sleeve, and laser rod employ a number of advantageous self-aligning and sealing features.

Abstract: An optical beam is made closer to diffraction limited by coupling it into a multi-mode guide, such as an optical fiber, of sufficient length to generate a stimulated Brillouin scattering (SBS) return beam with improved divergence. For this purpose the term .DELTA.kL is made substantially greater than .pi., where .DELTA.k is the difference in propagation vectors between the input and SBS beams, and L is the mutual interaction length of the input and SBS beams within the fiber. Beam amplification can also be provided by coupling a plurality of low power input beams that have respective wavelengths within the fiber's SBS linewidth into the fiber so that each of the input beams transfers energy into the SBS beam, which emerges with a power greater than that of any of its inputs. The beam cleanup and amplification functions are capable of operating with continuous wave or pulsed inputs.

Abstract: An apparatus for maintaining a crystal at a precisely controlled operating temperature over extended periods of time without significant thermal degradation of the crystal. The apparatus has thermally conducting walls. The walls define an inner hermetically sealed chamber for the crystal. Input and output windows are hermetically sealed to the input and output ends of the chamber. The inner surfaces of these windows are maintained at the operating temperature of the crystal to prevent fogging of the windows. Flexible thermal conducting layers are used between the crystal surfaces and the walls of the chamber to achieve uniform and continuous thermal contact therebetween, without mechanical stress to the crystal. The structure provides fast thermal response, controlled temperature in the crystal interaction region and stability of operation over extended periods of time. In one preferred embodiment, the crystal is held in suspended position within the chamber between a pair of spring-loaded plungers.

Abstract: A Raman laser (10) is provided using a pump laser (22) as a source of radiation at a first wavelength and a Raman cell (30) for converting the first wavelength radiation to a second wavelength. The pump laser (20) provides polarized radiation at a predetermined first wavelength which is focused by a focusing means (40) into a Raman medium (32) which converts radiation at the first wavelength to a predetermined second wavelength by Raman scattering processes. A reflection means (50) which is aligned normal to the first wavelength radiation is disposed between the pump laser (20) and focusing means (40). The reflection means is substantially 100% reflective of radiation at the second wavelength and substantially non-reflective of radiation at the first wavelength.

Abstract: A laser apparatus (10) has a coherent master oscillator radiation source (30) for driving a plurality of laser gain elements (20) positioned in a operationally parallel configuration so as to receive unamplified radiation (40) from master oscillator (30) and transmitting amplified radiation (44). Input means (60) couples portion of radiation (40) from master oscillator to each of said gain elements (20). Phase conjugate reflector means (80) operatively coupled to gain elements (20) reflects the phase conjugate of amplified radiation (44) back into the gain elements (20) where it is further amplified. Output coupling means (90) couples amplified radiation from the plurality of gain elements (20) out of the laser apparatus as a single coherent output beam of radiation.

Abstract: A laser apparatus (10) utilizing a master oscillator power amplifier configuration wherein a master oscillator (12) provides a source of low energy, high phase front quality, and high spectral purity radiation, injected into at least one lasing medium gain element (14) disposed along an optical path. Coupling means (16) is positioned to selectively couple a predetermined percentage of the master oscillator (12) radiation into the gain element (14) medium while preventing all but a predetermined percentage of any amplified radiation exiting the gain element (14) from re-entering the master oscillator (12). Phase conjugation means (20) is disposed along the optical path on the opposite side of the gain element (14) as the coupling means (16), for reflecting the phase conjugate of laser radiation incident thereon.

Abstract: Arrangements are disclosed for reciprocatively scanning a focused laser beam across an optical frequency converting crystal while deriving an output laser beam at the converted frequency along a stationary path. An effective elongated illumination pattern is provided for the crystal which reduces thermal gradients across the crystal, while the beam density at the crystal is sufficiently large so that high conversion efficiency may be realized.